For distribution, scale, and high availability (HA) purposes, a session initiation protocol (SIP) registrar, SIP proxy, or SIP application server may be implemented as a cluster rather than as a single node. In such clusters, when a SIP REGISTER message is received, the registration information may be saved into a data store so that the information can be accessed later (e.g., for authentication or for routing a call to a registered endpoint). Conventional implementations may use a single database that is common to the nodes within the cluster.
In these conventional approaches, nodes in the cluster processing the REGISTER or INVITE messages that may need to perform a lookup can contact that single database. One drawback of this approach is that such a single database may become a bottleneck as the number of nodes in the cluster increases. Other drawbacks associated with conventional approaches include a lack of scalability, and fail-over time during node failure.